Pocket knife with a weighing element

ABSTRACT

A pocket knife having at least one pull-out cutting tool or blade, provided on at least one side with a lateral covering covering said knife, and at least three blockable assembly axes which hold together the knife or the cutting tool in a pull-out or retracted position. A weighing element is arranged inside the pocket knife. Said element can be extracted about at least one of the axes or at least one other axis and/or is displaceably mounted during weighing. The weighing element is actively connected to a transmitting device in order to transmit the weight that is to be measured to a measuring sensor.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a 35 U.S.C. §371 national phase conversion ofInternational Application No. PCT/CH2003/000416 filed 25 Jun. 2003,which claims priority from Swiss patent application No. 1172/02 filed 4Jul. 2002.

BACKGROUND OF THE INVENTION

The present invention relates to a pocket knife and to a method forweighing a weight by means of a pocket knife.

WO 99/56918 discloses a multifunctional tool, inter alia in the form ofa pocket knife, which can be used as a weighing machine. In this case, aweighing element is provided which can be folded out of the pocket knifeand on which a weight can be suspended.

The exemplary embodiments described in this international patentapplication are kept rather general, and in particular theabove-mentioned pocket knife, when intended for use as a weighingmachine, leaves room for further developments.

SUMMARY OF THE INVENTION

In other words, one object of the present invention is to propose apocket knife for use as a weighing machine which can be produced in asimple and cost-effective manner which is suitable for mass production.

The invention proposes a pocket knife for use as a weighing machine.

One embodiment proposes a pocket knife, having at least one cutting toolwhich can be folded out, a side cover covering at least one side of theknife and at least three mounting spindles which hold the knife togetherand can lock the cutting tool in a folded-in or folded-out position,which pocket knife has a weighing element which is mounted such that itcan be folded out about one of the at least three spindles or at least afurther spindle and/or such that it can be moved during weighing.

In this case, the weighing element is operatively connected to atransmission arrangement for transmitting the weight to be weighed to ameasuring sensor.

The transmission arrangement preferably has a lever-like element whichis at least operatively connected to the weighing element in order totransmit the weight to be weighed in a lever-like manner to themeasuring sensor.

While the weighing element provided for weighing purposes can be pivotedor folded out of the body of the pocket knife, the lever-liketransmission element provided for transmitting the weight to be weighedis a part which remains in the knife, and the measuring sensor, to whichthe weight to be weighed is transmitted by the transmission element, ispreferably a micromechanical silicon sensor.

On the one hand, the weighing element, the transmission element and themeasuring sensor can be arranged on a pocket knife plane which isdirectly covered by the at least one side cover of the pocket knife, inwhich side cover the evaluation electronics and the display for themeasured weight are arranged. In accordance with a further embodiment,the weighing element, the transmission element and the measuring sensormay also be arranged on a plane formed centrally in the pocket knife,further tools such as a bottle opener, a can opener and the like beingarranged on the tool and pocket knife planes between the first-mentionedplane and the at least one side cover, having evaluation electronics anddisplay tools, said further tools leaving a through-opening free, whichextends transversely to the pocket knife plane, between the measuringsensor and one side cover. Through this opening the connection is madebetween the measuring sensor and the evaluation electronics. However,the connection between the measuring sensor and the evaluationelectronics may also be made by means of a so-called transpondertransmission, which means that no physical opening is required.

The invention also proposes a method for weighing a weight by means of apocket knife of the type defined according to the invention. In thiscase, the pocket knife is rocked or moved to and fro at least twice by aperson carrying out the weighing operation, as a result of which theweighing element, which is mounted such that it can move about one ofthe at least three mounting spindles of the pocket knife, is moved atleast twice through the 90° point, i.e. protruding downwardsperpendicular to the longitudinal axis of the pocket knife, a peak valuefor the weight to be determined being measured at least twice in eachcase, and these peak values, when averaged, giving the weight to bemeasured. Evaluation electronics are preferably used to continuouslydetect the force which is set by the pocket knife moving to and fro,and, in the event of approximately similar peak values, these values ortheir mean value is/are displayed as the weight to be measured. Afurther possibility consists in the use of a so-called Hall sensor, inwhich the position of the weighing member or weighing element isdetected. By a single tipping movement of the pocket knife, the Hallsensor detects the exact 90° position of the weighing member in relationto the longitudinal axis of the pocket knife, i.e. that the weighingmember protrudes precisely vertically such that it points downwards. Atthe same time in this 90° position the weight is detected at themeasuring sensor. The two values can be coupled, for example, by meansof a microprocessor.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained in more detail by way of example andwith reference to the attached figures, in which:

FIG. 1 shows a perspective illustration of a pocket knife according tothe invention with the weighing element folded out;

FIG. 2 shows a perspective illustration of a further embodiment of apocket knife according to the invention with the weighing element foldedout;

FIG. 3 shows a schematic illustration of the internal workings of apocket knife according to the invention, showing the elements relevantfor the weighing;

FIG. 4 shows a longitudinal section through the pocket knife planehaving elements essential to the weighing;

FIG. 5 shows a further arrangement of the elements relevant fordetermining a weight on the corresponding longitudinal plane of thepocket knife according to the invention;

FIG. 6 shows an alternative measuring arrangement in which a measuringsensor is provided directly on the weighing element;

FIG. 7 shows a schematic, perspective illustration of one embodiment ofa measuring sensor;

FIG. 8 shows a schematic illustration of an alternative bearingprinciple for transmitting the weight to be weighed from the weighingelement to the measuring sensor;

FIGS. 9 a and 9 b show the compensation of a possible angled position ofthe measuring element with respect to the longitudinal axis of thepocket knife, and

FIGS. 10 a and 10 b show a further compensation variant using a Hallsensor.

FIG. 11 is a cross-section view illustrating the knife blade foldablysecured by one of the mounting spindles.

DESCRIPTION OF A PREFERRED EMBODIMENT

FIG. 1 shows a perspective illustration of a pocket knife 1 according tothe invention, having different tools 3, 4 and 5 arranged on differentplanes, for example knife blades, scissors, awls, bottle openers, canopeners etc. The various tool planes are covered on both sides by covers6 and 7, and the covers and the various tools are held together by atleast two longitudinal spindles 9 and 10 which are arranged to thegreatest possible extent in the end region. In order for it to bepossible for the tools to be positioned such that they can be locked ineach case in the folded-in or else in the folded-out state, clampingelements are provided, which have a corresponding longitudinal extentwhich cannot be seen in FIG. 1, are held on one side in the two endspindles 9 and 10 and are held and clamped by a further spindle 11extending transversely to the pocket knife. These three spindles 9, 10and 11 are generally at least provided in pocket knives. If awls,corkscrews and the like are provided, generally at least four mounting,holding and/or locking spindles are provided which extend transverselyto the pocket knife plane.

Provided in the pocket knife 1 described according to the invention suchthat it can pivot about the spindle 11 and such that it is held on saidspindle is a weighing element 13 which can be pivoted or folded out ofthe pocket knife body in the same way as, for example, a blade, in orderto be brought into the position illustrated in FIG. 1. A weight, whichcan be determined using further elements, sensors and the like providedin the pocket knife, can now be suspended on this hook-like weighingelement 13. The measured weight can be read off from a display 17arranged in one of the two side covers 6 and 7. More details will begiven below on the internal workings of the pocket knife according tothe invention with reference to FIG. 3 and the subsequent figures.

FIG. 2 shows a further embodiment of a pocket knife according to theinvention, where the weighing element 13 is arranged such that it canpivot on one of the two mounting spindles 9 or 10 arranged in the endregion instead of on the spindle 11. It is irrelevant per se where theweighing element is arranged, but one of the already existing mountingor holding or locking spindles is preferably used for arranging theweighing element 13.

FIG. 3 shows a schematic illustration of the internal workings of apocket knife according to the invention, similar to that shown inFIG. 1. In this case, the weighing element 13 together with atransmission element 21 is mounted on the mounting spindle 11 such thatit can move or pivot as freely as possible, with the result that theweight suspended on the weighing element 13 can be transmitted to ameasuring sensor 23 via a hinge-like connection 14 and the transmissionelement 21, arranged in the interior of the pocket knife. The measuringsensor 23 for its part is connected to evaluation electronics 25, whichare arranged in the side cover 6. Finally, the determined weight can beread off from a display 17.

In the subsequent FIG. 4, a further, possible arrangement is illustratedfor transmitting the weight suspended on the weighing element 13 to themeasuring sensor 23. In this case, FIG. 4 shows a schematic illustrationof a longitudinal section through the pocket knife according to theinvention along that plane on which the various elements responsible forthe weighing and measuring are arranged. In this case, analogously toFIGS. 1 and 3, the measuring element 13, which can be pivoted out of theknife body and is in the form of a hook, is fixed on a spindle 11extending transversely to the plane. The transverse spindle 11 is inthis case coupled to a lever-like transmission element 21 which is fixedsuch that it can pivot in the manner of a lever about a spindle 31. Thistransmission element 21 is operatively connected to a furthertransmission element 21′ which is fixed such that it can rotate about afurther spindle 31′. This further transmission element 21′ finallypresses against the measuring sensor 23 via a ball-like element 24, theweight suspended on the measuring element 13 finally being detected bysaid measuring sensor 23. Also indicated in FIG. 4 are two tools whichare conventionally arranged per se in a pocket knife and which are, forexample, a can opener or screwdriver 5 and a can opener 5′.

With reference to FIG. 4 it should also be mentioned that the measuringelement 13 is also illustrated in the folded-in state and is identifiedby a dashed leader provided with the reference numeral 13′. It can alsobe seen from FIG. 4 that the measuring sensor 23 is freely accessible,despite the tools 5 and 5′ indicated, at least on one side, that is tosay on the side where the tools 5 and 5′ indicated are arranged. Thearrangement for measuring and transmitting the weight to be measureddoes not necessarily need to be arranged directly beneath a side coverof the pocket knife but may also be provided in the central region,which is of advantage for accurate measurement. As a result of the factthat a through-opening is free to the side cover owing to the selectionof the tools 5 and 5′ indicated, wire, contact-pin or contact-tabtransmission of the weight detected by the measuring sensor to theevaluation electronics in the corresponding side cover is possible.

FIG. 5 in turn shows, using an analogous section, a measuring andtransmission arrangement, primarily the transmission element 21 nowbeing mounted such that it can move and rotate about a spindle ormounting spindle 11 of the pocket knife, and the weighing element 13being fixedly connected to the transmission element 21 such that it canpivot about a further pivot spindle 31″. In turn, the weighing element13 is arranged such that it can rotate into or out of the pocket knifebody. If a weight is now suspended on the weighing element 13, theweight is transmitted directly to the transmission element 21 via thepivot spindle 31″, and said transmission element 21 transmits the weightto the measuring sensor 23 via an intermediate element 24 owing to thefact that it is mounted such that it can rotate about the spindle 11.

In contrast to the above embodiments, the signal detected by themeasuring sensor can also be transmitted to the evaluation electronicsin wireless fashion by means of electromagnetic coupling by themeasuring sensor 23 containing a coil, and by transmission to theevaluation microprocessor taking place, for example, by means oftransponder transmission. The measuring sensor in this case containspassive encoding and/or evaluation electronics. On the one hand, themeasurement energy is transmitted to the measuring sensor and theencoding and/or evaluation electronics by means of electromagneticcoupling. The encoding and/or evaluation electronics in this casemodulate the transmission energy, which can be evaluated by the sensor.This principle is known as the tag or transponder principle. Thisembodiment has proved to be particularly advantageous when assembling apocket knife where it is easily possible for any contact tabs, wires orthe like extending from the measuring sensor to the evaluationelectronics to be damaged given the relatively rough assemblyconditions. This risk is not encountered in the case of wirelesstransmission.

FIG. 6 shows an alternative variant for detecting a weight by means of apocket knife. FIG. 6 shows only a weighing element in longitudinalsection, which is mounted by way of example such that it can be foldedout of the pocket knife about the spindle 11. The weight is detected inthis case directly at the weighing element by a part 71 being providedwhich is weaker than the rest of the weighing element. When a weight issuspended on the weighing element 13, the weaker point 71 is extendedslightly in the longitudinal direction or in the direction of the arrow,and this extension, as is illustrated schematically in FIG. 6 b, isdetected, for example, by means of a measuring strip 73. The measuringstrip 73 may have the same design as the elongation measuring stripbridge 45, described below with reference to FIG. 7, of a measuringsensor 23. The measured value may in turn be transmitted by means ofso-called transponder transmission to evaluation electronics or to themicroprocessor in the lateral pocket knife shell, where finally also thedetected weight is displayed.

FIG. 7 finally shows an embodiment of a preferred measuring sensor, tobe precise of a micromechanical silicon sensor. In this case, the weighttransmitted by the transmission element 21 (not illustrated) to anintermediate element 24 is transmitted to the silicon sensor 41, inwhich measuring resistors 45 in the form of a measuring bridge arearranged. This intermediate element 24 is advantageously a ball-likeelement. The measuring principle of this micromechanical silicon sensorcorresponds to that of elongation measuring strip bridges 45, which arefitted to a silicon chip 43 and have connections 46. The advantages ofthis measuring technique are as follows:

-   -   very short paths (a few μm);    -   since the silicon is monocrystalline, there is no material        fatigue in contrast to conventional sensors on metal;    -   direct temperature measurement on the same small silicon        crystal, thus very accurate evaluation of the measuring bridge        possible.

FIGS. 8 a and 8 b show schematic illustrations of a further variant ofthe measurement or transmission and mounting principle of the weight tobe detected. The suspended weight is transmitted to the measuring sensor23 via the intermediate element 24 using the measuring element 13 whichis connected to a transmission element or transmission lever 21 suchthat it can rotate freely on a spindle 11. In this case, transmissiontakes place by means of a tipping movement of the transmission element21 about a resilient bearing 81 which is formed between the transmissionelement 21 and a retaining plate 83. The difference between theillustrations in FIGS. 8 a and 8 b is merely the fact that in one casethe retaining plate and the resilient bearing 81 are arranged in FIG. 8a between the weighing element 13 and the sensor 23, whereas in FIG. 8 bthe bearing 81 is arranged on the transmission element 21 at the end. Inorder to prevent the measuring sensor 23, such as a silicon sensor, frombeing damaged, in each case a stop 28 can also be seen in FIGS. 8 a and8 b, against which the transmission element 21 rests when the weighingelement 13 is subjected to a certain maximum load. This means that theweighing potential is limited, i.e. the measuring device shown in FIGS.8 a and 8 b can only be used up to a certain maximum weight.

The significant advantage of transmitting the weight by means of theresilient bearing described is the fact that the bearing is free oflubricant and there is no risk of wear. However, it is important that inthe spring system the yield point is never exceeded, with the resultthat 100° resetting to the starting position is always possible.

On the other hand, there is a certain risk of wear in the arrangementsshown in FIGS. 1 to 7 and it is therefore important that the diversejoints are either in the form of friction bearings or of ball bearingsor flexural bearings, and that the diverse elements are not mounted suchthat the detected weight is falsified in any way.

A further essential point is the fact that the weighing force can onlybe measured correctly when the force is largely at rights angles to thelongitudinal axis of the pocket knife. At an angle other than 90° thereis a deviation.

Since it is of course easily possible for the angle not to be precisely90° when a pocket knife is held, an angled position of the hook mustthus be compensated for in some way. This compensation is illustratedschematically in FIGS. 9 a and 9 b. In principle, the compensation canbe corrected by a sine function, as illustrated in FIG. 9 b.Compensation may thus be carried out using both electronic and/ormechanical methods.

In accordance with one preferred embodiment, the following procedure isproposed according to the invention. The procedure is a so-calledrocking method in which a user moves the pocket knife or the measuringbody to and fro at least twice. The weighing element 13 is thus moved toand fro owing to its ability to move as freely as possible about thefixing spindle 11. Evaluation electronics continuously detect the forcevalues. When there has been a pivotal movement twice through the 90°point, i.e. when the weighing hook has passed at least twice through theposition extending perpendicularly downwards, there must be twoapproximately similar peak values for the measured force. These peakvalues represent the weight to be measured. Small, short instances ofinterference are filtered out by digital filtering methods. In addition,a plausibility check is carried out.

Either this peak value can then be displayed as the weight on thedisplay 17 or else a mean value for the different peak values can bedetermined and displayed.

As an alternative to this, however, the angular position of the hook mayalso be detected. Using, in addition to the measuring sensor 23, asecond sensor which can detect the angular position of the hook withrespect to the longitudinal extent of the pocket knife, the angle ismeasured, and the measured force is corrected according to the sinefunction, illustrated in FIG. 9 b. Suitable sensors are as follows:

-   -   Hall Sensor: A Hall sensor is pushed together with the force        sensor into the measuring body. The angular position is detected        together with a magnet which is fixed on the hook.    -   optical sensor    -   potentiometer having a resistance path and a slider.

FIGS. 10 a and 10 b show the arrangement of an above-mentioned Hallsensor 91, by means of which the deviation from the position of theweighing element 13 can be determined. FIG. 10 a shows that the Hallsensor 91 is arranged opposite the end region 93 of the weighing element13, this end region 93 being magnetic. If the weighing element 13, as isillustrated in FIG. 10 b, now moves with the end region 93 along theline 97 about the spindle 11, this deviation from the central positionis detected by the Hall sensor. On the other hand, however, the weightsuspended on the weighing element is of course also transmitted by thetransmission element 21 to the measuring sensor 23 or detected by saidmeasuring sensor 23. The two values detected by the Hall sensor 91 andthe measuring sensor 23 are combined in a microprocessor 95, and theweight detected in the measuring sensor 23 is correspondingly correctedby the deviation of the element 13. The arrangement of a Hall sensormeans that it is thus no longer necessary for there to be any rocking,as described with reference to FIGS. 9 a and 9 b.

However, it is also possible to envisage mechanical compensation. Inthis method, the point of action for the lever transmission is moved, upto a certain degree, depending on the angled position of the hook.

FIG. 11 illustrates knife blade 3 foldably secured by mounting spindle10 to allow knife blade 3 to pivot about mounting spindle 10.

The embodiment illustrated in FIGS. 1 to 11 and elements according tothe invention are of course only examples which can be altered ormodified in any desired manner or which can be replaced by furtherelements. The fundamental purpose of the figures is to explain thepresent invention in more detail using examples. In particular, theprecise arrangement of the various elements, the selection of themeasuring sensor system, the evaluation electronics, the display, thedesign of the pocket knife itself etc. can be modified in any desiredmanner within the scope of the present invention.

1. A pocket knife for measuring a weight of a load suspended therefrom,the pocket knife comprising: a body; at least one cutting tool or bladepositioned and configured to be folded out of the body; a side cover ofthe body covering at least one side of the at least one cutting tool orblade; at least three mounting spindles positioned and configured tofoldably secure the at least one cutting tool or blade to the body andoperable to lock the cutting tool in a folded-in or folded-out positionwith respect to the body; a measuring sensor positioned at the body andoperable to measure the weight; and a transmission arrangementconfigured to pivot about one spindle of the at least three mountingspindles; a weighing element mounted to the body such that the weighingelement is foldable out of the body, the weighing element beingconfigured to receive the load and to transmit to the transmissionarrangement in a first force direction the weight of the load; and thetransmission arrangement configured to change a force direction of theload from the first force direction to a torque force rotating about theone spindle by the pivoting about the one spindle when the weighingelement receives the load, wherein the measuring sensor is operativelyconnected to the weighing element by the transmission arrangement fortransmitting the torque force as the weight of the load directly to themeasuring sensor.
 2. The pocket knife as claimed in claim 1, wherein thetransmission arrangement includes a lever element having a first end anda second end, the lever element positioned and configured to be at leastoperatively connected to the weighing element in order to transmit theweight to the measuring sensor by the first end of the lever elementmoving down and the second end moving up in a lever manner in responseto the weight transmitted.
 3. The pocket knife as claimed in claim 1,wherein the weighing element is foldable out of the body about onespindle of the at least three mounting spindles.
 4. The pocket knife asclaimed in claim 3, wherein the weighing element is mounted to onespindle of the at least three mounting spindles such that the weighingelement, according to the weight of the load, moves transversely to thespindle within a pre-specified distance.
 5. The pocket knife as claimedin claim 1, wherein the weighing element and the transmissionarrangement are mounted in such a manner that there is no or littlefriction resisting their movement relative to the body.
 6. The pocketknife as claimed in claim 5, wherein the weighing element and thetransmission arrangement are mounted by bearings selected from the groupconsisting of friction bearings, ball bearings and flexural bearings. 7.The pocket knife as claimed in claim 1, wherein the weighing element andthe transmission arrangement are mounted in a resilient manner whereinthe transmission element is connected to a retaining element via aresilient mounting spindle.
 8. The pocket knife as claimed in claim 1,further comprising a measuring arrangement for detecting an angularposition of the weighing element based on a longitudinal axis of theknife body.
 9. The pocket knife as claimed in claim 8, wherein themeasuring arrangement is selected from the group consisting of a Hallsensor, an optical sensor and a potentiometer having a resistance pathand a slide.
 10. The pocket knife as claimed in claim 1, furthercomprising an evaluation microprocessor operable for receiving datadetected by the measuring sensor and transmitted to the microprocessorin wireless fashion.
 11. The pocket knife as claimed in claim 1, furthercomprising evaluation electronics connected to the measuring sensoroperable to determine the measured weight.